Assessment of relevant factors and relationships concerning human dermal exposure to pesticides in greenhouse applications

Health risks of pest control and disinfection workers after the COVID-19 outbreak in South Korea

The exposure patterns of pest control and disinfection workers have changed after the coronavirus disease 2019 (COVID-19) outbreak, but the health risks of chemical exposure have not been assessed. We identified these workers' chemical exposure patterns and risks before and after the COVID-19 outbreak. We used data conducted between 2018 (pre-pandemic) and 2021 (post-pandemic) from three-year cross-sectional surveys on pest control and disinfection workers. Inhalation and dermal exposure concentrations were estimated using equations based on a biocidal product risk assessment model from the Korean National Institute of Environmental Research. The non-carcinogenic and carcinogenic risks of chemicals were calculated using the United States Environmental Protection Agency risk assessment model. We found that the annual work frequency (50th percentile) of foggers using disinfectants increased the most among all the work types, from 140 uses/year to 176 uses/year after the COVID-19 outbreak. Moreover, all chemicals' non-carcinogenic and carcinogenic risks increased regardless of exposure routes. In the worst scenario (95th percentile), the margin of exposure for citric acid, benzethonium chloride, benzyl-C12-16-alkyldimethyl chlorides, and sodium chlorite of inhalation exposure, and isopropyl alcohol and benzyl-C12-16-alkyldimethyl chlorides of dermal exposure were acceptable (>100) before the COVID-19 outbreak but became unacceptable (<100) after the COVID-19 outbreak. Carcinogenic risks of dichlorvos from inhalation and dermal exposure were above acceptable levels (>10-6) before and after the COVID-19 outbreak but comparatively high after the COVID-19 outbreak. Additionally, significantly more workers experienced health symptoms after the COVID-19 outbreak (p<0.05), with the most common being muscle lethargy (31%), skin/face stinging (28.7%), and breath shortness/neck pain (24.1%).

Exposure and risk assessment for agricultural workers during chlorothalonil and flubendiamide treatments in pepper fields

Pesticides are indispensable tools in modern agriculture for enhancing crop productivity. However, the inherent toxicity of pesticides raises significant concerns regarding human exposure, particularly among agricultural workers. This study investigated the exposure and associated risks of two commonly used pesticides in open-field pepper cultivation, namely, chlorothalonil and flubendiamide, in the Republic of Korea. We used a comprehensive approach, encompassing dermal and inhalation exposure measurements in agricultural workers during two critical scenarios: mixing/loading and application. Results revealed that during mixing/loading, dermal exposure to chlorothalonil was 3.33 mg (0.0002% of the total active ingredient [a.i.]), while flubendiamide exposure amounted to 0.173 mg (0.0001% of the a.i.). Conversely, dermal exposure increased significantly during application to 648 mg (chlorothalonil) and 93.1 mg (flubendiamide), representing 0.037% and 0.065% of the total a.i., respectively. Inhalation exposure was also evident, with chlorothalonil and flubendiamide exposure levels varying across scenarios. Notably, the risk assessment using the Risk Index (RI) indicated acceptable risk of exposure during mixing/loading but raised concerns during application, where all RIs exceeded 1, signifying potential risk. We suggest implementing additional personal protective equipment (PPE) during pesticide application, such as gowns and lower-body PPE, to mitigate these risks.

The greenhouse work environment: a modifier of occupational pesticide exposure?

Greenhouses are enclosed structures which have various characteristics that enhance crop productivity, but the implications for workers' pesticide exposure and uptake are not well understood. A narrative literature review was conducted to explore the mechanism/s of interactions between greenhouse characteristics and occupational pesticide exposure. Using a "work", "worker" and "workplace" conceptual framework, the greenhouse environment (hot and humid microclimate, limited space and dense crop arrangements) combines with work characteristics (high work and pesticide use intensity, multi-tasking, predominantly manual spraying techniques and quick reentry to treated farms) to potentially increase occupational pesticide exposure, compared with open field farming. Greenhouse environments, are variable but have been shown to influence pesticide availability, route, pathways and frequency of exposure, deposition and distribution on a worker's body as well as use and performance of exposure control methods. Training programs can emphasize the differences in exposure potential between greenhouse and open field farming. Development of tailored guidelines for exposure control strategies to better suit the level of uniqueness of greenhouse agriculture seems warranted.

Risk of dermal and inhalation exposure to chlorantraniliprole assessed by using whole-body dosimetry in Korea

BACKGROUND

We determined the characteristics and evaluated associated risks of sprayed pesticide exposure among workers cultivating Korean cabbage. The test pesticide, a mixture of 3% chlorantraniliprole and 4% indoxacarb wettable granules diluted 2000 times, was sprayed on Korean cabbage within a 3000 m² area in Goesan, Korea. Dermal exposures were measured using a whole-body dosimetry method.

RESULTS

Exposure to chlorantraniliprole was observed among ten individuals, ranging from 140.4 to 4234.0 µg person^-1 . The legs were the most prominent exposure area (86.35%), with the face being the least exposed (0.06%). Exposure risk was assessed by calculating the margin of safety (MOS) on the exposure amount for each body part. The MOS based on dermal and inhalation exposure doses ranged from 59 to 1765.

CONCLUSION

Exposure was the greatest for the legs, probably as a result of the low height of the crop and the use of a long-wand sprayer. An MOS value >1 indicates a low risk for applicators using this method of application. However, with tall crops, exposure level and MOS values can vary widely, as MOS increases or decreases based on exposure dose. Therefore, future research is needed to better understand appropriate safety precautions when working with potent pesticides. © 2018 Society of Chemical Industry.

Evaluating Glyphosate Exposure Routes and Their Contribution to Total Body Burden: A Study Among Amenity Horticulturalists

OBJECTIVE

To evaluate determinants of dermal and inadvertent ingestion exposure and assess their contribution to total body burden among amenity horticultural users using glyphosate-based pesticide products.

METHODS

A dermal and inadvertent ingestion exposure assessment was completed alongside a biomonitoring study among amenity horticultural workers. Linear mixed effect regression models were elaborated to evaluate determinants of exposure and their contribution to total body burden.

RESULTS

A total of 343 wipe and glove samples were collected from 20 workers across 29 work tasks. Geometric mean (GM) glyphosate concentrations of 0.01, 0.04 and 0.05 µg cm-2 were obtained on wipes from the workers' perioral region and left and right hands, respectively. For disposable and reusable gloves, respectively, GM glyphosate concentrations of 0.43 and 7.99 µg cm-2 were detected. The combined hand and perioral region glyphosate concentrations explained 40% of the variance in the urinary (µg l-1) biomonitoring data.

CONCLUSION

To the author's knowledge, this is the first study to have investigated both dermal and inadvertent exposure to glyphosate and their contribution to total body burden. Data show the dermal exposure is the prominent route of exposure in comparison to inadvertent ingestion but inadvertent ingestion may contribute to overall body burden. The study also identified potential exposure to non-pesticide users in the workplace and para-occupational exposures.

Potential dermal and inhalation exposure to imidacloprid and risk assessment among applicators during treatment in cotton field in China

Quantifying operator exposure to pesticides is a key component of the decision-making procedure for risk assessment. China is the largest cotton-planting country in the world. Dense cotton planting patterns and pesticide overuse potentially place Chinese cotton farmers at high levels of exposure risk. Using whole-body dosimetry during backpack spraying application in cotton filed, the present study monitored potential dermal and inhalation exposure to the insecticide imidacloprid. For forward spraying (when the operators walked forward), the total potential dermal and inhalation exposure was 2059mg/kg of active ingredient (ai), corresponding to 0.21% of the applied quantity of the insecticide. However, the total exposure of backward walking (188mg/kg of ai) was approximately 11 times lower than that of forward walking. The upper body parts (head, chest, back and arms) were the most exposed. The potential inhalation exposure contributed to <0.1% of the total exposure. The exposure risk to imidacloprid inherent in these agricultural procedures was evaluated by margin of exposure values and was found to be safe under the present cotton treatment scenarios. In general, similar body exposure and distribution between Allura Red and imidacloprid verify Allura Red's feasibility as an environmentally friendly pesticide surrogate for exposure assessment.

Potential Dermal Exposure to Flonicamid and Risk Assessment of Applicators During Treatment in Apple Orchards

Exposure and risk assessments of flonicamid for applicators were performed in apple orchards in Korea. Fifteen experiments were done with two experienced applicators under typical field conditions using a speed sprayer. In this study, cotton gloves, socks, masks, and dermal patches were used to monitor potential dermal exposure to flonicamid, and personal air samplers with XAD-2 resin and glass fiber filter were used to monitor potential inhalation exposure. The analytical methods were validated for the limit of detection, limit of quantitation, reproducibility, linearity of the calibration curve, and recovery of flonicamid from various exposure matrices. The results were encouraging and acceptable for an exposure study. The applicability of XAD-2 resin was evaluated via a trapping efficiency and breakthrough test. During the mixing/loading, the average total dermal exposure was 22.6 μg of flonicamid, corresponding to 4.5×10(-5)% of the prepared amount. For the spraying, the potential dermal exposure was 9.32 mg, and the ratio to applied amount was 1.9 × 10(-2%). The primary exposed body parts were the thigh (2.90 mg), upper arm (1.75 mg), and lower leg (1.66 mg). By comparison, absorbable quantity of exposure was small, only 1.62 μg (3.2×10(-6)%). The margin of safety (MOS) were calculated for risk assessment, in all sets of trials, MOS > 1, indicating the exposure level of flonicamid was considered to be safe in apple orchards. Although this was a limited study, it provided a good estimate of flonicamid exposure for orchard applicators.

Risk assessment of applicators to chlorpyrifos through dermal contact and inhalation at different maize plant heights in China

Dermal and respiratory exposure assessments and risk assessment for applicators were performed with 48% chlorpyrifos EC. The chlorpyrifos was applied with lever-operated knapsacks under three spraying environments, namely, average maize field heights of 62 cm (A1), 108 cm (A2), and 212 cm (A3). The whole body dosimetry technique was applied to collect dermal exposure samples including cotton protective garments, gloves, socks, and hats. A personal air monitor equipped with an XAD-2 resin was used for respiratory exposure assessment. Without personal protective equipment (PPE) the total potential dermal exposure (PDE) was 27.8, 90.6, and 462.1 mL h(-1) under A1, A2, and A3 spraying environments, respectively. In addition, with the change in the maize plant height, the major exposure parts on the applicators were also different. Under single-layer garment and glove protection circumstances, internal dermal exposure (IDE) was 3.37 mL h(-1) for A1, 4.28 mL h(-1) for A2, and 18.32 mL h(-1) for A3. Potential inhalation exposure (PIE) was detected in A3, but it was not detected in A1 and A2. For risk assessment, the margin of safety (MOS) was calculated from the PDE or IDE and PIE. The MOS values for the three spraying environments were <1 under no PPE and single-layer garment and glove protection circumstances, indicating high possibility of health risk. However, with double protective garments, the MOS values for A1 and A2 cases were all >1, but the MOS was <1 in the A3 case.

Assessment of the exposure of workers to the insecticide imidacloprid during application on various field crops by a hand-held power sprayer

Exposure assessment and risk assessment for imidacloprid were conducted for agricultural workers through mixing/loading and application with a power sprayer in four kinds of crop fields. The spray suspension was prepared with 10% wettable powder (250 g) for 5 min and applied on field crops for 1 h. A patch method and a personal air sampler with XAD-2 resin were used to monitor the dermal and inhalation exposure, respectively. In mixing/loading, the total dermal exposure on the whole body was 0.2 (cucumber) to 2.0 (apple) mg and the most exposed part of body was the hand (48-100% of total exposure). During the application of imidacloprid, whole dermal exposure was in the range of 2.9 (apple) to 9.5 (green pepper) mg. The primary sites exposed to pesticides were legs (51-79% of total exposure) in cucumber, green pepper, and paddy fields, whereas the primary sites were hands (35% of total exposure) in the apple field. The inhalation exposure was determined to be 0.2 (paddy) to 2.8 (cucumber) μg and 0.2 (paddy) to 3.0 (cucumber) μg during mixing/loading and application, respectively. The absorbable quantity of exposure and the margin of safety were determined for risk assessment. Workers were exposed through inhalation as 23-93 and 2-11% of the absorbable quantity of exposure during mixing and application, respectively. The margin of safety of all cases was much higher than 1, indicating the lowest possibility of risk.

Effects of nozzle type and spray angle on spray deposition in ivy pot plants

BACKGROUND

Fewer plant protection products are now authorised for use in ornamental growings. Frequent spraying with the same product or a suboptimal technique can lead to resistance in pests and diseases. Better application techniques could improve the sustainable use of the plant protection products still available. Spray boom systems--instead of the still predominantly used spray guns--might improve crop protection management in greenhouses considerably. The effect of nozzle type, spray pressure and spray angle on spray deposition and coverage in ivy pot plants was studied, with a focus on crop penetration and spraying the bottom side of the leaves in this dense crop.

RESULTS

The experiments showed a significant and important effect of collector position on deposition and coverage in the plant. Although spray deposition and coverage on the bottom side of the leaves are generally low, they could be improved 3.0-4.9-fold using the appropriate application technique.

CONCLUSIONS

When using a spray boom in a dense crop, the nozzle choice, spray pressure and spray angle should be well considered. The hollow-cone, the air-inclusion flat-fan and the standard flat-fan nozzle with an inclined spray angle performed best because of the effect of swirling droplets, droplets with a high momentum and droplet direction respectively.

Effect of spray application technique on spray deposition in greenhouse strawberries and tomatoes

BACKGROUND

Increasingly, Flemish greenhouse growers are using spray booms instead of spray guns to apply plant protection products. Although the advantages of spray booms are well known, growers still have many questions concerning nozzle choice and settings. Spray deposition using a vertical spray boom in tomatoes and strawberries was compared with reference spray equipment. Five different settings of nozzle type, size and pressure were tested with the spray boom.

RESULTS

In general, the standard vertical spray boom performed better than the reference spray equipment in strawberries (spray gun) and in tomatoes (air-assisted sprayer). Nozzle type and settings significantly affected spray deposition and crop penetration. Highest overall deposits in strawberries were achieved using air-inclusion or extended-range nozzles. In tomatoes, the extended-range nozzles and the twin air-inclusion nozzles performed best. Using smaller-size extended-range nozzles above the recommended pressure range resulted in lower deposits, especially inside the crop canopy.

CONCLUSIONS

The use of a vertical spray boom is a promising technique for applying plant protection products in a safe and efficient way in tomatoes and strawberries, and nozzle choice and setting should be carefully considered.

Potential dermal pesticide exposure affected by greenhouse spray application technique

BACKGROUND

Operator safety is still one of the main problems concerning greenhouse spray applications in South European horticulture. The main objective of this study was to compare potential dermal exposure (PDE) between traditional handheld spray application techniques (i.e. a standard spray gun walking forwards, a spray lance walking forwards and backwards) and novel spray application techniques with spray booms (i.e. a trolley, the Fumimatic and the Fumicar).

RESULTS

PDE varied from 19.7 mL h(-1) for the Fumimatic to 460 mL h(-1) for the spray lance walking forwards. Walking backwards reduced PDE by a factor 7. With the trolley, Fumimatic and Fumicar, PDE was respectively 20, 60 and 8 times lower than with the standard spray gun. With the spray lance, PDE was about 2.5 times higher than with the spray gun. Pesticide distribution over the operator's body was non-uniform and correlated strongly with the application technique. With the traditional techniques, exposure to the legs and feet represents 60-80% of the total exposure.

CONCLUSIONS

Novel spray application techniques using spray booms greatly decrease operator exposure because the operator is not walking directly into the spray cloud and the sprayed crop, and because of their higher capacity. Depending on the type of spray application, different parts of the body need to be protected most.

Environmental and biological monitoring of exposure to organophosphorus pesticides: application to occupationally and non-occupationally exposed adult populations

The purpose of the study was to assess non-dietary exposure of workers and the general population in the Paris area to some organophosphorus (OP) pesticides. In total, 21 workers from different occupational places (two greenhouses, three florist shops and three veterinary departments) and 20 subjects assumed to be non-occupationally exposed were recruited. Indoor air, hand wipes, and three first morning urine samples were collected. Seven OPs were measured by GC/ECD and GC/TSD, and six urinary dialkylphosphate metabolites by GC/PFPD. All indoor air samples from the workplaces and only one-third of the samples from the residences contained at least one of the seven OPs. However, almost all participants were dermally exposed to OPs. Total OP indoor air and cutaneous levels were significantly higher for workers than for the general population (air median = 185 pmol/m3 versus nondetectable, P < 0.0001; hands median = 1250 pmol/hands versus 475 pmol/hands, P = 0.03). From the air, gardeners and florists were mainly exposed to methyl-OPs and veterinary staff to ethyl-OPs (mainly diazinon). From their hands, all subjects were exposed to methyl-OPs, with gardeners and florists exposed to somewhat but not significantly higher levels. Ethyl-OPs were more found frequently and at higher levels on the hands of veterinary workers. Total OP levels in indoor air and from hand wipes were significantly correlated (Spearman R = 0.34, P = 0.03). DAP detection frequencies and levels were not different between workers and the general population (workers median=168 nmol/g creat and general population median = 241 nmol/g creat, P = 0.31), and did not correlate with air or hand levels. Subjects not occupationally exposed showed significant residential exposure to OPs, more frequently from their hands than from the air. Different occupations were associated with different exposure profiles and levels. The lack of differences in DAP levels between the different groups of exposure suggests that dietary exposure to OP residues and exposure to other OPs are involved.

Risk assessment of human exposure to cypermethrin during treatment of mandarin fields

The potential dermal and respiratory exposure assessment and risk assessment for applicator were performed with cypermethrin EC. The pesticide was applied on a mandarin field using a power sprayer. Gloves were used for the hand exposure assessment, mask for face, and dermal patches for the other parts of the body. Personal air monitor equipped with a XAD-2 resin was used for the respiratory exposure assessment. During the application of cypermethrin in the field, the rate of potential dermal exposure ranged from 28.1 to 58.8 mg/h. The major exposure parts were upper-arms (22.1-24.6%) and legs (thigh and shin, 28.3-29.2%) for females and thigh (21.0-46.9%) and hand (14.9-19.3%) for males. Females were exposed more than males. No exposure was detected from the respiratory monitoring. For risk assessment, the potential dermal exposure (PDE), the absorbable quantity of exposure (AQE), and the margin of safety (MOS) were calculated. Among those four risk assessments, MOS was < 1 in only trial I, which indicated any possibility of risk. However, in the others, the possibility of risk was little. Moreover, the safe work time ranged from 3.61 h to 9.69 h.

Assessment of potential (inhalation and dermal) and actual exposure to acetamiprid by greenhouse applicators using liquid chromatography–tandem mass spectrometry

New analytical methods based on liquid chromatography with electrospray tandem mass spectrometry (LC-MS/MS) have been developed and validated for assessing the exposure of greenhouse workers to acetamiprid. Both ambient (potential inhalation and dermal exposure) and internal dose (biological monitoring of urine samples) measurements were carried out. Potential inhalation exposure was assessed using Chromosorb 102 cartridges connected to air personal samplers. Potential dermal exposure was estimated by using whole body dosimetry. The measurement of actual exposure was done by analyzing the parent compound in urine samples of the applicators, after a solid-phase extraction (SPE) step. The methods showed a good accuracy (72-92%), precision (2-13%) and lower limits (few microg l(-1)). The validated approaches have been applied to assess potential and actual exposure of agricultural workers spraying acetamiprid in greenhouses. The results shown the need to wear personal protective equipment (suits) in order to reduce the absorbed dose of acetamiprid.